ssl: RecursionError on Python3.6+; Thanks to justdoit0823@github and Gevent developers

https://github.com/eventlet/eventlet/issues/371

eventlet/green/ssl.py

@@ -401,6 +401,26 @@ if hasattr(__ssl, 'SSLContext'):
         def wrap_socket(self, sock, *a, **kw):
             return GreenSSLSocket(sock, *a, _context=self, **kw)
 
+        # https://github.com/eventlet/eventlet/issues/371
+        # Thanks to Gevent developers for sharing patch to this problem.
+        if hasattr(_original_sslcontext.options, 'setter'):
+            # In 3.6, these became properties. They want to access the
+            # property __set__ method in the superclass, and they do so by using
+            # super(SSLContext, SSLContext). But we rebind SSLContext when we monkey
+            # patch, which causes infinite recursion.
+            # https://github.com/python/cpython/commit/328067c468f82e4ec1b5c510a4e84509e010f296
+            @_original_sslcontext.options.setter
+            def options(self, value):
+                super(_original_sslcontext, _original_sslcontext).options.__set__(self, value)
+
+            @_original_sslcontext.verify_flags.setter
+            def verify_flags(self, value):
+                super(_original_sslcontext, _original_sslcontext).verify_flags.__set__(self, value)
+
+            @_original_sslcontext.verify_mode.setter
+            def verify_mode(self, value):
+                super(_original_sslcontext, _original_sslcontext).verify_mode.__set__(self, value)
+
     SSLContext = GreenSSLContext
 
     if hasattr(__ssl, 'create_default_context'):

tests/isolated/green_ssl_py36_properties.py

@@ -0,0 +1,16 @@
+__test__ = False
+
+
+if __name__ == '__main__':
+    import eventlet
+    eventlet.monkey_patch()
+
+    try:
+        eventlet.wrap_ssl(
+            eventlet.listen(('localhost', 0)),
+            certfile='does-not-exist',
+            keyfile='does-not-exist',
+            server_side=True)
+    except IOError as ex:
+        assert ex.errno == 2
+        print('pass')